The purpose of the Television Ophthalmoscopy/Image Processor (TOIP) Project is to develop an instrument which analyzes television images of the ocular fundus and extracts clinically-useful measurements from the images. Further, it is an objective of the project to determine the value of these measurements in specific clinical situations. The Television Ophthalmoscope instrument consists of: (1) A television and optical system which views the fundus through a conventional Zeiss fundus camera and creates a television signal; (2) A computer-controlled light source of our design which provides illumination of variable duration and spectral content; (3) A digital computer with pecially designed hardware extensions to permit processing of the television images; each program is tailored to process a specific class of measurements. Four basic categories of image measurements are under investigation: (1) Quantitative angiography: a series of television frames is scanned after injection of a tracer; these images are automatically analyzed to extract volume flow rates and circulation times; (2) Oximetry: pairs of television images are processed to determine percent oxygen saturation of the blood in individual retinal vessels; (3) Multispectral reflectance: as many as nineteen images are scanned, each under illumination of a different wavelength range; these images are analyzed to extract reflectance signatures from features of arbitrary shape and orientation, and to measure retinal photopigment kinetics and physiological state: (4) NADH microfluorometry: a low-light-level television camera images fluorescence of reduced pyridine nucleotide in retinal mitochondria to continuously monitor intracellular oxidation-reduction states in vivo.